ABA/JH Swap by Moljinar

By diyauto
( 4 )


Compliments of Moljinar @ vwvortex.com


By the pricking of my thumbs, something wicked this way comes! 

Cue remix of "Bad to the Bone" and "I am Ironman" mashup...

Now that the mood is set let's look at the easiest and cheapest way to enhance the performance of your A1 whether Cabby or Rabbit.

The ABA/JH hybrid motor swap. 

Is that ol' JH is leaking like a sieve and can't outrun the family station wagon any more? Time to swap engines. But it's not as hard to do as you might think. 

You must have a modicum of mechanical skills. If you can change your own clutch you can do this swap. 

First you need an ABA engine. I got mine from a junkyard for $150, complete 

with serpentine belt drives and other bolted on stuff. You WON'T need the fuel injection harness and parts unless you plan to swap over all that stuff but for this swap we won't be doing that. I've seen several $250 ABAs for sale lately with complete harnesses and parts so that's your price range. Detemining the mileage on an ABA is a bit difficult since the A3s these engines were in had electronic odometers which won't be working in the junkyard.


ABA's are 2.0 liter 4 cylinder 8v engines ( 114 hp) found in 1992-present Volkswagen Golf, Volkswagen Jetta, Volkswagen Passat and Volkswagen New Beetles. The heads are crossflow types. meaning the exhaust and intakes are on opposite sides of the head. While you can make that work in an A1 you're asking for more work. Our swap will use the existing JH head (solid lifter or hydraulic doesn't matter) That allows us to not have to do any rewiring, no plumbing changes to the fuel injection regardless of DigiFant or CIS, no relocation of components.

Once you have your engine you'll need to clean it up and verify it's reasonably in good shape. Once that's done I pull the head. Leave the intake and exhaust manifolds on it it still attached. It makes it easier to handle and they won't be needed. Removal of the head is the same as any 8V VW engine. Drain the coolant out first. While you're at it drain the oil. Eventually you'll have this block upside down and all the oil will drain out and make a mess. Trust me on this. 

Check out the bores. You should be able to see a light crosshatching and not

much if any carbon build-up on the pistons. Turn the engine upside down and pull the flywheel and pressure plate off. The usual ABA flywheel and clutch is too big to use with your 020 transmission. You won't need it anyway. Now pull off the oil pan. Inspect the pan for frothy brown stuff, shavings, small parts, rodents and sludge. If you want to get really crazy pull the bearing caps and check the crank journals for wear. Or not if you trust the source of your engine. Clean out the oil pan and paint it while it's off. 

Clean up the engine and paint it. Pull the serp belt brackets off if you are so 

inclined. They bolt back on easy enough.


You'll need a few things to make this work. 

1. 16V head gasket. Only way to make the JH head work on the ABA. 

2. Breather block off kit. 


Not actually mandatory but makes life much easier on you later. Make sure you install the freeze plug but you'll need to remove the serp belt bracket to get access. See Techtonics Tuning for the kit. 



3. Distributor gear and bushing Kit. 



This is required if you use a distributor from a usual 8V engine. You can also 

decide to swap a CIS or Digifant shutter wheel onto the ABA distributor. Here 

are some links to study while you make your decision.

4. Knock sensor ECU and harness. See above links for more information. This

combo should give you a compression ratio of 10:1 which will cause 

predetonation if the gas is bad and timing isn't right. And it destroys engines 

so VW came up with this to solve the problem. 

5. Exhaust "solution"

The ABA is 16mm taller than your old block. This causes 2 problems. The 

throttle lever may hit on the rain tray and catch/stick. You'll need to bend it 

out of the way. The stock A1 exhaust may no longer be able to reach the exhaust manifold without bumping into the body. Solutions are to cut and extend the pipe, put in longer studs and make a 16mm spacer. Most 4 into 1 headers and 4-2-1 headers will clear fine. TT used to make a race downpipe for the dual outlet manifold and it clears fine as well. You could also use the ABA exhaust manifold on your JH head and Techtonic's stainless steel flex downpipe. 

Expensive but comes with a short shift kit as well and should last forever. 



6. Serp belt AC delete kit. 



Use this if you don't have/want an AC compressor in the serp belt system. It 

uses a VR6 serp belt "pulley' for the water pump. And a shorter serp belt.

That's about it. Simple list. 

Pull your JH head off the engine that's still in the car. Again do not remove

the intake and exhaust manifolds unless you really have a need to. Drain the fluids now. It'll make a mess later if you don't. Trust me. 

Disconnect everything. Careful with the wiring since it's 25 years old and will 

crack on you if bent too far. Pull the engine and transmission out. Separate 

the two. Pull the old engine off to the side. 

Clean up the engine bay while it's empty. You'll thank yourself later.

Put together the ABA except for the head/manifolds. The upper timing cover will not fit correctly, frankly I got rid of mine. Modify it if you feel the need. 

Make sure the serp belt system is together and working. This is a good time to put on a new timing belt. Use clutch, flywheel and pressure plate from original engine. Tip: good time to put in new clutch. While you're at it put in a new 16V pressure plate to handle the new power levels you'll be rocking. What the heck use a lightened flywheel as well it has it's advantage if only to make it easier to remove the oilpan screws. Paint the timing marks now while you have a chance. 


Take the oil sensors and temp sensors out of the old block and put them into the proper holes on the ABA. You'll need to reuse the black water pipe that wraps around the engine. 

Last time, go around the engine and make sure it's clean, tight, painted and 

ready to go. Put the new block in the car. Bolt up the tranny. Now put on the 16V headgasket. It may not fit since the line up pilot stud was too big to fit in 

the hole in the gasket. Very carefully drill it out to fit. Deburr it as well. 

Once it's on you can put the head on. Once torqued on correctly you can start hooking things up. Feed it water and oil as needed.

Set the static timing. Install the distributor. Time it. If you use the knock 

sensor setup make sure it's hooked up correctly. 

Since you never replaced the fuel injection system it's ready to go. Once 

everything is hooked up you're ready to go!


If you choose to use the distributor gear kit you'll need to drill out the pin. 

Look at both ends of the pin. One side is obviously split. On that side 

centerpunch a hole (and make sure it's centered!) Drill there with a 5/16" 

drill bit. If it's a fresh bit it'll go thru with no problem. The shaft is much 

harder than the pin and if the drill bits a bit off it'll recenter rather than 

drill into the shaft. Hammering out the pin is a major pain, don't bother 

trying. Put the bushing on first then the gear. The roll pin in the kit can be 

removed later and easily. 


The throttle cable end will bump into the raintray. You must dent this 

otherwise the cable will stick or fall off. Neither is good. 

The passenger side motor mount needs t either have the old alternator mount under it or a spacer of some sort. I chose to eliminate the old mount and used 8mm nuts, drilled out, as spacers. Nice and clean. 


Power steering is a bitch so far. The original brackets won't work and even if they did the pulleys aren't close to lining up. I'm working on a solution but so far PS isn't available. 


This is a strong setup. Lots of comfortable torque. Very rev happy. 

I'll add more as I think of it. 




Mine misses by about a 1/4 to 1/2 " . I've heard of others having issues but mine clears like a champ. Use as big hammer and flatten the rail there.


Got the gauges hooked back up and looks like I'm getting 28 -39 mpg!


NY_Fam in the MK1 forum sliced open several dozen 8V intake manifolds and found all of them roughly the same on port size. He has a service where he will take your manifold and open it up and smooth all the transitions as well. Proven good for 6-10 hp on a stock engine!! I'm going to have it done myself someday.

Meanwhile the best thing to do is a larger throttle body such as from an Audi turbo 5000 or an A2 (requires modification) and then open up the manifold opening to match the larger throttle opening.

The exhuast is loud because I have a straight thru muffler (Dynomax I think) and with the race downpipe, no cat and TT cat-back system it's failry loud-ish. Add the punch of a ABA and it's louder. Nice bark and crackle. SOunds like a large tractor at intowen cruising but open 'er up and everyone takes notice!

Simply putting a regular hi-po muffler like a Borla on there sound be reasonably quite for you. 

KNock sensor wiring gets done tomorrow I think. Would've not been needed but I couldn't get the harness out in one piece so I have wires to splice. I have CIS-E distributor ready to go. 

If you are keeping the AC you'll have to use the AC that comes with the ABA IF you intend to keep the serp belt system. AND My info says that the AC lines won't bolt up without modification. You may want to visit someone's A3 to see what's what. If you use the JH's brackets and belts you'll be ok . And at that point powersteering would be no problem. 

The ABA in an A3chassis has no passenger side mount. It uses a funky rear/passenger mount you won't need/can't use. The holes were there for my A1 passenger mount but I know recall the threads weren't in good shape. I had to chase the threads with a tap to clean them out. Then my mount went on fine. As for the stock mount I have no issues. In fact the ABA seems to idle smoother and vibrate less. Possibly an effect of the longer rods? 

The more I drive this car I'm convinced this is what VW should've put in our cars from the beginning. Or at least made a GT version with it

The usual TT upgrade system is fine, no larger size needed unless you're thinking of turbo'ing it and even then maybe not. Size for size's sake is not really needed. The ABA downpipe TT makes for this swap is hefty in the first place and that's usually the major choke point of most systems. And yeah, too big will kill your back pressure (which actually helps out with torque.)

Frankly the biggest gotcha with this swap is the distributor setup. Today everyone cringes to think of using a centrifugal/vacuum advanced distributor with a high (10:1) compression engine. Frankly I remember several decades of high compression engines with no knock control but let's just agree that using VWs knock control system is what you want to do. 

You can't use a regular CIS distributor because it has cent/vacuum advance and can't be computer controlled. You'll need a CIS-E or Digifant distributor, neither of which have any timing adjustment in them. The both have 4-hole/shutter wheels which you'll need if you are using either the CIS-E knock sensor box (a separate ECU that hooks up to the ignition unit and the distributor) or the Digifant ECU which controls the fuel injection AND the ignition/knock. The ABA distributor has only 1 shutter wheel opening. It signals cylinder #1 while the OBD1 trigger wheel in the crankcase senses the crank position to allow the ECU to figure out the timing advance to use. This could be used if you are using the ABA's native fuel injection system or a standalone such as MegaSquirt or others.

Now with all that in mind and needing to drive the car immediately I put in the usual CIS distributor, set the timing to basic specs and unhooked the vacuum advance. Running premium with no more than 20* of total advance I'm doing fine with no apparent detonation. Ron will tell you that you can't sense the micro detonation that can destroy things and that's probably true. But it's a stop gap that seems to do fine for now. NOT a long -term solution unless you want to re-curve the distributor (lord the 60's and 70's were fun) Also once you put TTs gear on it's easy to remove and put on another distributor

The AC issue is not an issue for me. Do as you feel like. But I will say the serp belt setup is awesome!!

I have no upper timing belt cover ( I spent too much on the pretty timing gear, why cover it up?) so getting to the mount was no big deal. AS I said earlier it bolted right up. Only needed a spacer to make it lie down properly. 


I'm indeed close to solving the powersteering crisis but I'll not revela that until I'm in the midst of it. 

Meanwhile despite the taller engine I've found the upper strut brace as sold by EuroSport and TT do clear the head with no real issue. I'll have pics soon.


Small update. 

After a few weeks of driving I can now recommend that anyone doing this swap will want to dimple/flatten the section of frame rail where the Serp belt tensioner sticks out. Although mine isn't hitting normally it does on hard left turns. I figure this is due to the passenger mount sagging differently between different cars.


Firstly I helped out my clearance problem by jacking up the engine until I could slide in a piece of rubber tubing with a 8mm bolt in side. That keeps the mount from dropping which moves the engine closer to the frame rail. Being mostly rubber it doesn't increase the vibration any.

Secondly, yeehaaaw!! I have a A3 powersteering pump and bracket in hand and after a bit of experimentation have figured out how to make our powersteering work with the ABA and a serp belt setup. I have pics and when I finish the install I'll post the solution.


Here's few pics to whet your whistle.

The A3 ps system uses a heavier set of brackets which hold a cradle which holds the ps pump. The cradle is pivoted at one end and adjusted via a geared adjustment similar to some VW alternators. All in all rather solid. 

The A1/A2 ps pump is physically identical to the A3 pump as far as external dimensions and mounting points go. Only the hose connection is different. So simply remove the A3 pump and put in the A1 pump. 

But the A3 hub is longer, about 1/2". To use the A1 pump we need to remove the hubs and trade them. That's where I'm at right now. I thought I had a 3-jaw puller but I don't. May rent one tonight. 

OR...... you could probably use the entire A1 PS setup and use the A3 hub and get it to work. Personally I prefer the sturdiness of the A3 setup.



As you found out the knock sensor CPU curves the spark advance/retard as needed. The ABA also has a trigger wheel should you eventually decide to use standalone engine/spark management.


The stock brackets should work fine but be advised that the threaded bolt holes my need re-tapped. Mine were rough if they hadn't been used before.

As to the gasket it's due to making sure the proper holes are uncovered. I didn't check to see exactly where the differences were.


The ABA compressor doesn't clear the front crossmember according to what I read.


In the usual serp belt set up the alternator is NOT adjustable. It's firmly mounted.


From what I've gathered putting the AC compressor in on the serp belt system in the MK1 chassis is doable IF you put the compressor in AFTER the engine is in. And the MK1 compressor will work in the brackets IF you change the pulley to the serp belt pulley available from here...http://www.jegs.com/i/March+Performa.../P475/10002/-1

This is what I'm planning for this summer.


Most 8V heads have various oil and coolant passages but not always in the same place. To make sure the proper ones match up the 16V gasket is used because the holes are in the right places to allow the flow.